Many mobile phones and tablets include cameras designed to take pictures. These cameras typically use a CMOS (complementary metal-oxide semiconductor) sensor with an infrared cut-off filter designed to block near infrared photons from reaching the imaging sensor, while passing visible light. The IR cut-off filter prevents infrared radiation from distorting colors in images from colors as generally perceived by the human eye. While this results in more natural looking images, conventional mobile devices are unsuitable for detecting fluorescent emission at IR wavelengths without removal of the included infrared cut-off filter.